Outstanding post. Probably the most honest evaluation of joint surgery I've heard. My take-aways:
the main benefit will be the pain relief.
There is a risk of making things worse, you will likely trade some of your mobility and not be guaranteed your strength.
If you don't have pain you have the risk of being dissatisfied that your painless joint has been replaced with an imitation joint often that is a bit clunkier/warmer/more swollen than it was before